He was deeply grieving the death of his family.

Infrared astronomy provides a new perspective on understanding the universe.

I stabbed the needle for the injection.

The Riemann sum is a method for approximately calculating the integral of a function.

His performance is generally good.

He followed the footprints left on the snow.

I made a mistake.

He was feeling loneliness.

He provided a detailed explanation to elucidate the issue.

This job is suitable for him.